I had the same issue, in the back passenger side of the vehical in the storage compartment for the jack, the bulb will sometime get bounced a little...which will cause the light to come on.. Check and be sure the bulb is fully installed and that the jack is installed properly also. If the jack is not properly in the storage compartment it will move the wires to the bulb causing it to get loose.
The only way I discovered it was I put the jack in right while the van was on. (It was rattling and driving me nuts). My husband noticed the light go out as I moved a wire.
Hope this helps you | 
